Silver halide emulsion stabilized with a polymer derived from aziridinyl azine compounds



United States Patent ()fiice 3,502,477 Patented Mar. 24, 1970 ABSTRACT OF THE DISCLOSURE An anti-foggant agent produced by heating a compound shown by the general formula in water wherein R is selected from the group consisting of hydrogen, methyl and ethyl. A photographic material contains a silver-halide emulsion layer which contains said reaction product.

The present invention relates to a siliver halide photographic material containing an improved anti-foggant.

It has been well known that the photographic sensitivity of a silver halide photographic emulsion is effec tively increased by the addition of active gelatin, a compound containing an labile sulfur, a noble metal salt, a olyalkylene oxide derivative and the like. On the other hand, however, fogging tendency is generally increased by the addition of such a compound and hence, in order to prevent the formation of fog, the addition of antifoggant is necessary.

Many anti-foggants have been reported for preventing the formation of such fog. However, although these compounds have the ability to reduce the formation of fog during manufacturing or during preservation, there is a drawback that the photographic sensitivity is reduced by the addition of these compounds.

Therefore, an object of this invention is to provide a photographic emulsion. in which the fog formation is prevented and the preservability is improved without reducing the sensitivity.

Another object of this invention is to provide a method for suppressing the formation of fog in a photographically sensitive material when it is preserved under severe conditions of high temperature and high humidity.

A further object of this invention is to provide a photographically sensitive emulsion in which changes of the senstiized emulsion in sensitivity and contrast are reduced.

Still another object of this invention is to provide a method for preventing the formation of fog in the case of pre-hardening the film of the photographic silver halide-gelatin emulsion in a Formalin bath and the like, prior to developing, without reducing the sensitivity of the photographically sensitive material.

The inventors have found as the result of various investigations that these purposes can be attained by the addition to the silver halide emulsion of the product obtained by heating an aqueous solution or a water-containing organic solvent solution of a compound shown by the general formula:

wherein R represents a hydrogen atom, a methyl group or an ethyl group.

The solution may be suitably heated at temperatures of from 40 to 100 C. for minutes to 5 hours and a suitable concentration of compound (I) in the solution is from 0.5 to 10% by weight. Further, in the case of adding preliminary inorganic acids, such as hydrochloric acid or sulfuric acid, organic acids, such as acetic acid or citric acid, inorganic bases, such as sodium hyi droxide, potassium hydroxide, ammonium hydroxide, in- 29 organic acid salts such as sodium sulfate; or organic acid salts such as potassium phthalate or sodium acetate to the solution, the above mentioned product may be obtained by heating in mild condition rather than hot in the case without adding these compounds.

30 By the proper combination of the above-mentioned reaction conditions initial anti-foggant of this invention can be obtained in general but, in particular, it s preferable to heat a aqueous solution of 12% by weight of compound (I) for 2 to 3 hours at 90 to 100 C. However, it

' should be understood that the invention is not limited to the ranges of these conditions.

An aqueous solution or an aqueous dispersion containing the above-mentioned reaction-product of compound (I) may be used in situ or after adjusting the pH desirably by adding an acid or an alkali but, if necessary, it may be formed into a solid by drying and prior to use dissolved again in a solvent giving no bad effects on photographic silver halide emulsions, such as water, alcohols, acetone, dimethylformamide, dimethyl sulfoxide and the like.

The aforesaid anti-foggants used in this invention have excellent anti-fogging power to light-sensitive materials as mentioned above but do not adversely effect photographic characteristics. 1

The compound shown by general Formula I, a raw material of the anti-foggant of this invention is known as a hardening agent for photographic gelatin (cf., Japanese Patent No. 309,487 and US. Patent No. 2,983,611), but the above-mentioned reaction-product of compound (I) shows no hardening action for gelatin. This means that the anti-foggant of this invention has no bridge-making aziridinyl group in the molecule different from the compound shown by general Formula I and it can be understood that a part of the aziridinyl group bonded to the triazine nucleus of compound (I) is opened by heating in the presence of water to form the initial polymerization product and other part of it is converted into inactive substituents such as hydroxy-ethyl-amino group.

This fact is supported, as the result of analyzing the content of the aziridinyl group in the anti-foggant used in this invention (for example, by a method described in Analytical Chemistry, vol. 35, page 1063) and measuring the molecular weight thereof (for example, by using a vapour-pressure osmotic-pressure meter made by Memo- 70 lab Inc.), by the facts that the content of aziridinyl group is 0 or a negligible amount, if any and the average molecular Weight of the anti-foggant is 400 to 600. Further,

it has been confirmed that when the anti-foggant of this invention is compared with compound (I) by a usual thin-layer chromatography in which ethyl acetate is used as a solvent for developing, silica gel as adsorbent, and Orange I as developer, compound (I) gives a spot at the point wherein the R: value is about 0.15 while the antifoggant of this invention gives a spot at the original place, that is, no movement is observed about the compound.

The compound (I) has a decomposition range of 139 145 C., but the anti-foggant of this invention decomposes at the higher ranges, i.e., over 200 C.

Furthermore, solubilities of the anti-foggant differ from the compound (I) as shown in the following table:

Solvent Compound (I) Anti-foggant Water Very soluble Soluble.

Ethyl alcohol... 11 Slightly soluble. Dimethyl formamide. Very soluble Soluble. Methylene chloride ..do Insoluble.

B enzene Soluble D o.

Ethyl acetate ..d Do.

Still further, the differences of the structures of these compounds is shown by their infrared absorption spectra:

It is clear that aziridine rings do not remain in the antifoggant.

Additionally, the viscosity of the anti-foggant is higher than that of the compound (1). While the compound (I) has an intrinsic viscosity of 0.021 in dimethyl formamide at 35 C., the anti-foggant of this invention has an intrinsic viscosity of 0.03 to 0.10 in the same condition.

The typical examples of preparing the anti-foggant of this invention are shown below:

(a) Into distilled water is dissolved g. of 2,4,6-tris (1'-aziridinyl)-1,3,5-triazine to make 1000 ml. of the aqueous solution and the solution is placed in a 2 liter reaction vessel equipped with an agitator, a thermometer and a reflux condenser. The solution is heated on a steam bath for 2 hours at 98100 C. with stirring and then cooled to room temperature. Thus, an aqueous solution containing 1 g. 100 ml. of the anti-foggant of this invention is prepared. A part of this solution is treated through a centrifuge to separate a solid and the solid is subjected to freeze-drying. The compound thus obtained shows a decomposition range of 247 to 275 C. and intrinsic viscosity of 0.067 in dimethyl formamide at 35 C.

(b) Into distilled Water is dissolved 20 g. of 2,4,6-tris (2'-methyl-1-aziridinyl)-1,3,5-triazine to make 1000 ml. of the aqueous solution and the solution is placed in the vessel same as in term (a) and boiled for 1 hour by refiuxing followed by cooling to room temperature. Thus, an aqueous solution containing 2 g./l00 ml. of the antifoggant is prepared. A solid obtained by the same procedure as (a) shows a decomposition range of 250 to 260 C. and an intrinsic viscosity of 0.047 in dimethyl formamide at 35 C.

(c) Into distilled water is dissolved 20 g. of 2,4,6-tris (1'-aziridinyl)-1,3,5-triazine to make 1000 ml. of the aqueous solution. The solution is treated, after adding 50 ml. of an aqueous solution of 0.1 N potassium biphthalate, as in term (a) except that the heating temperature is 60 C. and the heating period is 30 minutes. Thus, an aqueous solution containing 2 g./100 ml. of the anti-foggant is prepared. A solid obtained by the same procedure as (a) shows a decomposition range of 270 to 275 C. and an intrinsic viscosity of 0.080 in dimethyl formamide at 35 C.

(d) The pH of the aqueous solution containing 1 g./ ml. of the anti-foggant obtained in term (a) is 9.7 and in this example, the pH is adjusted to 5.2 by adding 1 N hydrochloric acid. A solid obtained by the same procedure as (a) shows a decomposition range of 210 to 215 C. and an intrinsic viscosity of 0.071 in dimethyl formamide at 35 C.

(e) By repeating the procedure as in term (0) using 30 ml. of an aqueous solution of 0.1 N sodium sulfate instead of the aqueous biphthalate solution, an aqueous solution containing 2 g./100 ml. of the anti-foggant is prepared. A solid obtained by the same procedure as (a) shows a decomposition range of 255 to 270 C. and an intrinsic viscosity of 0.062 in dimethyl formamide at 35 C.

(f) Into about 500 ml. of distilled water is dissolved 30 g. of 2,4,6-tris(l'-aziridinyl)-1,3,5-triazine and the solution is, after the addition of 30 ml. of 1 N hydrochloric acid, diluted with distilled water into 1000 ml. By repeating the procedure as in term (a) except that the heating temperature is 40 C. and the heating period is 1 hour, an aqueous solution containing 3 g./100 ml. of the antifoggant is prepared. A solid obtained by the same procedure as (a) shows a decomposition range of 24l246 C. and an intrinsic viscosity of 0.093 in dimethyl formamide at 35 C.

(g) By repeating the procedure same as in term (a) using 2,4,6 tris(2 ethyl-1-aziridinyl)-1,3,5-triazine instead of 2,4,6-tris(1'-aziridinyl)-1,3,5-triazine, an aqueous solution containing 1 g./100 ml. of the anti-foggant is prepared. A solid obtained by the same procedure as (a) shows a decomposition range of 215220 C. and intrinsic viscosity of 0.034 in dimethyl formamide at 35 C.

The anti-foggant of this invention, that is, the initial polymerization product of the compound shown by general Formula I may be used alone or as a mixture thereof, or together with other stabilizer.

The anti-foggant of this invention may be added in an emulsion at any steps before the emulsion is coated on a support but is preferably added at a step between afterripening and coating. There is no limit about the addition of the anti-foggant but 0.01 to 50 g. per 1 mol of silver halide is preferable in a silver halide emulsion layer, and 0.05 to 250 g. per 1 kg. of gelatin is preferable in an adjacent layer such as a gelatino protective layer or a gelatino intermediate layer.

The invention is applicable to black and white negative emulsions, X-ray photographic emulsions, color photographic emulsions of the type wherein the emulsion contains a coupler and a type wherein the coupler is contained in a developer, and in particular, better results are obtained in the case of applying to gelatine silver iodobromide emulsions. However, of course the invention is applicable to other various silver halide emulsions.

The photographic silver halide emulsion of this invention may be sensitized with a compound containing unstable sulfur, such as, ammonium thiosulfate or allyl thiourea (e.g., cf., P. Glatkides, Chimie Photographique 2 em Edition, Publication Photocinema, Paul Montel, Paris, 1 957, pages 297-299), with a gold compound such as a complex salt of mono-valent gold and thicyanic acid (cf., ibid.; page 301), with a polyalkylene oxide derivative, or combinations thereof. Also, the photographic silver halide emulsion of this invention may be sensitized optically by adding an optical sensitizer, such as cyanine dye or merocyanin dye.

The invention will further be explained by the following examples:

EXAMPLE 1 To a sulfur-sensitized and gold-sensitized high speed gelatino silver iodobromide emulsion for use in negative type photographic material, was added the anti-foggant prepared by the above-mentioned method in term (a) or (b) and coated on a film base and dried. Thus obtained photographic film was exposed on a NSG II type sensitometer (made by Tokyo Shibaura Electric Co.) and then developed for 8 minutes at 20 C. in a developing solution having the following composition:

N-methyl-p-aminophenol sulfate-2 g. Sodium sulfite (anhydrous)l g. Hydroquinone g.

Water to makel liter.

The results of the comparative tests applied to the case where the above-described photographic film was used and the case where a control photographic film prepared by the same conditions as above but not containing the anti-fogging agent are shown in the following table.

As shown in the table, the formation of fog was suppressed elfectively when the anti-foggant of this invention was added.

EXAMPLE 2 The anti-foggant prepared by the process shown in term (c) was incorporated in a gelatino silver-iodo-bromide high-sensitive emulsion for X-ray photographic material sensitized with a sulfur-containing sensitizer and a gold-containing sensitzer, and the emulsion was coated on a film base and dried. The photographic film was exposed on an NSG II type sensitometer and developed in a developing solution having the following composition for 6 minutes at 20 C.

N-methyl-p-aminophenol sulfate-2 g. Sodium sulfite (anhydrous)80 g. Hydroquiuone-S g. Sodium carbonate (anhydrous)40 g. Potassium bromide2 g. Water to make 1 liter.

The results of comparing the case of this invention as shown above and that where the same emulsion but not containing the anti-foggant was used are shown in the following table.

Amount (g./1 mol Relative AgX) sensitivity Fog None 100 0. 19 Anti-foggant (c) 1. 5 98 0. 16 3. 0 94 0. 12

As shown in the above table, the formation of fog was clearly suppressed by the addition of the anti-foggant of this invention.

EXAMPLE 3 Sodium pyrophosphate-ZO g. Sodium sulfate-50 g. Formaldehyde (37%)-17 ml. Sodium hydroxide (l0%)1 ml. Water to make 1 liter.

The film was then rinsed with water for 4 minutes at 27 C. and developed for 7 minutes at 27 C. in the developing solution having the following composition and fixed:

N-methyl-p-aminophenol sulfate1 g. Sodium sulfite (anhydrous)60 g. Hydroquinone-l0 g.

Sodium carbonate (mono-hydrate)40 g. Potassium bromide-5 g.

Potassium thiocyanate1.5 g.

Potassium iodide (0.1%)-5 ml.

Sodium hydroxide2 g.

Water to make 1 liter.

The film was tested for the prevention of fogging in the first development and compared with the photographic film not containing the anti-foggant treated as in the above case. The results are shown in the following table.

Amount (g./1 mol Relative AgX) sensitivity Fog None 100 0.85 Anti-foggant (a) 1 1 115 0. 24 2.2 103 0.11 Antl-ioggant (g) 1. 7 112 0.15 3.4 102 0.06

By the addition of the anti-foggant, the formation of fog was clearly suppressed.

The anti-foggant prepared by the above-mentioned in term (e) or (f) was incorporated in a 5% gelatin solution, and 5 m1. of the solution was coated on a dry plate which was previously coated with a gelatino-silver iodobromide emulsion for reversal color photographic material sensitized with a sulfur-containing sensitizer and a gold-containing sensitizer.

The thus obtained, double-coated, dry plate was exposed on an NSG II type sensitometer and developed for 7 minutes as 27 C. in the developing solution having the same composition as in Example 3.

The thus obtained dry plate was compared with a dry plate prepared under the same conditions, except that the anti-foggant was not added. The results are shown in the following table:

Amount (mg/5 ml.

of 5% Relative gelatin) sensitivity Fog None 100 0. 18 Anti-ioggant (e) 1. O 98 0. 1 2. 0 97 0. 1 Anti-foggant (f) 18. 0 97 0. 1 36. 0 0. 0

As is clear from the table, the formation of fog was remarkably prevented by the addition of the anti foggant.

EXAMPLE 5 The anti-foggant prepared by the method shown in terms (a) or term (b) was incorporated in a gelatino- -silver, iodo bromide emulsion for reversal color photographic material sensitized with a sulfur-containing sensitizer and a gold-containing sensitizer. The emulsion was coated base and dried. The film was exposed and subjected to the following treatments:

The compositions of the above treating baths are as follows:

(1) Pre-hardening composition (same as in Example 3) (2) The negative development composition (same as in Example 3) (3) The color developing solution:

N,N'-diethyl paraamino aniline hydrochloride Sodium carbonate (mono-hydrate)20.0 g.

Potassium bromide-0.3 g.

Potassium iodide (0.1% )-2.0 ml.

4-(paratoluene sulfonamido)-omega-benzoy1 acetanilide1.0 g.

Sodium hydroxide4.0 g.

Water to make 1 liter.

Silver bleaching solution:

Potassium ferricyanide-60 g.

Potassium bromide--2O g.

Water to make 1 liter.

Developing solution:

Sodium thiosulfate100 g.

Sodium sulfite15 g.

Water to make 1 liter.

The thus obtained film was compared with films made without adding the anti-foggant of this invention. The results are shown in the following table:

Amount Charac- (g./1 mol Maximum teristic AgX) density curve As shown in the results, the maximum density after color development is increased by reducing the formation of fog in the negative development.

EXAMPLE 6 The anti-foggant prepared by the method shown in term ((1) was incorporated in a sulfur-and-gold-sensitized gelatino-silver iodo-bromide color photographic emulsion containing as a coupler 1-hydroxy-4-sulfo-2-n-octadecylnaphthamide 20 parts of an alkaline aqueous solution of 5% of the above coupler (1 g. of the coupler was dissolved in 1.4 ml. of 1 N sodium hydroxide) was added into 100 parts of the emulsion and after adjusting the pH of the emulsion to 7.0 with the addition of citric acid, the emulsion was coated on a film base and dried. The film was exposed and color-developed in the usual colordeveloping solution using N,N-diethyl-paraamino aniline as shown below.

Further the film was subjected to bleaching and fixing to remove undeveloped silver halide and reduced silver.

The compositions of the color-developing solution, bleaching solution and fixing solution are as follows:

Color-developing solution:

N,N-diethylparaamino aniline sulfate2.0 g. Sodium sulfite2. 0 g. I Sodium carbonate (mono-hydrate)50.0 g. Hydroxylamine hydrochloride1.5 g. Potassium brornide1.0 g.

Water to make 1 liter.

The pH was adjusted to 10.8101 by using sodium hydroxide.

Bleaching solution:

Potassium ferricyanate100 g. Potassium bromide-20 g. Water to make 1 liter.

Fixing solution:

Sodium thiosulfate-200 g. Sodium sulfite (anhydrous)20 g.

8 Acetic acid (28%)45 g. Boric acid7.5 g. Potassium alum-20 g. Water to make 1 liter.

After treatment, the density was measured by using a red filter.

The case of this example was compared with the case without adding the anti-foggant and the results are shown in the following table.

*After aging for 2 days at; C., 80% RH.

From the above table it was clear that the Cyan fog was markedly prevented while the sensitivity was not much reduced. Moreover it should be noticed that the increase of fog after aging was effectively prevented when the anti-foggant was added.

EXAMPLE 7 The anti-foggant prepared by the method described in term (a) was incorporated in a sulfur-and-gold-sensitized gelatino silver iodo-bromide emulsion containing as a coupler 1-phenyl-3(3(N-propyl-N-octylamido)propioamido)-5-pyrazoline (10 parts of the emulsified dispersion of the above coupler (5 g. of the coupler was dissolved in 100 ml. of tricresyl phosphate by heating and the solution was emulsified-dispersed with stirring at 8090 C. in 100 g. of a 10% aqueous gelatin solution containing 8 ml. of an aqueous 5% solution of sodium dodecylbenzene sulfonate) was added in 100 parts of the emulsion) and the emulsion was coated on a film base and dried. Thus obtained photographic film was exposed and subjected to a usual color development containing N,N'-diethylparaamino aniline as the developer. Further, the thus developed film was bleached and fixed to remove undeveloped silver halide and reduced silver.

Amuont Magenta (g./1 mol Magenta relative AgX) fog sensitivity one 0. 13 Anti-foggant (a) 0. 7 0. 09 102 1. 4 0. 07 83 The results show that the formation of magenta fog is extremely reduced without reducing the sensitivity.

EXAMPLE 8 The anti-foggant prepared by the method described in term (d) was added to a sulfur-and-gold-sensitized gelatino silver bromo-chlon'de emulsion containing as a coupler 3;5-dicarboxy-4'-stearoylamido benzoyl acetoanilide (40 parts of a 5% aqueous alkali solution of the above coupler was added in 100 parts of the emulsion) and after adjusting the pH of the emulsion to 8.0, the emulsion was coated on a film base.

On the thus formed emulsion layer there was coated a red-sensitive sulfur sensitized silver bromo-chloride emulsion containing the above-mentioned anti-foggant and, as a coupler, 1-hydroxy-4+sulfo-2-n-octadecylnaphthamide. Into 100 parts of the emulsion there were added 10 parts 9 of an 0.025% methanol solution of 3'-allyl-6,7-benzo-3- ethyl 2 5'(2(1 ethyl 4 quinolinidene) ethylidene)- 4-oxo-thiathiazolinocyanine iodide and 25 parts of a 5% aqueous alkali solution of the above coupler followed by adjustment of the pH to 7.0.

On the thus formed emulsion layer there was further coated a green-sensitive sulfur-sensitized gelatinosilver chloride emulsion containing the above-mentioned antifoggant and, as a coupler, 1-((3'-sulfo-4'-phenoxy)benzene)-3-heptadecyl-5-pyrazolone. Into 100 parts of the emulsion there were added 5 parts of an 0.05% methanol solution of 3,3'-9-triethyl-5,5-dipheny1-oxacarbocyanine rhodanide and 18 parts of a 5% aqueous alkali solution of the above coupler followed by adjustment of the pH of the emulsion to 7.5. The emulsion was then dried.

The amounts of the three emulsions were chosen so as to be 6 micron thickness in each emulsion layer when dried.

The thus prepared color photographic film was exposed and subjected to the usual color development using a color developing solution containing N,N-diethylparaamino aniline as the developer.

The film was further bleached and fixed to remove undeveloped silver halide and reduced silver. The conditions of the applied treatments were as follows:

(1) Color development, 20 C., for 10 minutes (2) Water-rinsing, 20 C., for 2 minutes (3) First fixing, 20 C., for 5 minutes (4) Water-rinsing, 20 C., for 5 minutes (5) Bleaching, 20 C., for 5 minutes (6) Second fixing, 20 C., for 5 minutes (7) Water-rinsing, 20 (3., for 10 minutes Antl-foggant (d) amount (g.l1 mol AgX) Yellow Cyan Magenta l Blue-sensitive layer.

2 Red-sensitive layer.

3 Green-sensitive layer.

(1) fog, (II) relative sensitivity.

As shown in the above results, the fog formation was remarkably reduced without during sensitivity in the case adding the anti-foggant.

By using other reaction products of compound (I) prepared under other conditions than those described in terms (a) to (g) wherein compound (I) is heated in the presence of water, almost the same results were obtained.

What is claimed is:

1. A photographic material comprising at least Ollu silver halide emulsion layer on a support, said emulsion layer containing a reaction product prepared prior to addition to the emulsion by heating to at least 40 C. water and 0.5 to by weight of a compound having the formula:

wherein R is selected from the group consisting of hydrogen, methyl and ethyl, the reaction product characterized in that it decomposes at temperatures above 200 C., is essentially free of aziridinyl groups, and has an intrinsic viscosity of from 0.03 to 0.10 in dimethyl formamide at 35 C.

2. The photographic material of claim 1 wherein said silver halide emulsion layer contains said reaction product in an amount of between 0.01 to 50 g. per mole of silver halide.

3. The photographic material of claim 1 wherein said reaction product is prepared by heating said aqueous solution at a temperature of between 40100 C.

4. The photographic material of claim 1 wherein said reaction product is prepared by heating said aqueous solution for a period of between 10 minutes to about 5 hours.

5. A photographic material comprising at least one silver halide emulsion layer on a support and a layer adjacent to said emulsion layer, said adjacent layer containing a reaction product prepared prior to addition to the adjacent layer by heating to at least 40 C. water and 0.5 to 10% by weight of a compound having the formula:

wherein R is selected from the group consisting of hydrogen, methyl and ethyl, the reaction product characterized in that it decomposes at temperatures above 200 C., is essentially free of aziridinyl groups, and has an intrinsic viscosity of from 0.03 to 0.10 in dimethyl formamide at 35 C.

6. The photographic material of claim 1 wherein said adjacent layer is a gelatino protective layer or a gelatino intermediate layer which contains said reaction prod uct in an amount of between 0.05-250 g. per kg. of gelatin in said layer.

References Cited UNITED STATES PATENTS 2,983,611 5/1961 Allen et a1. 96-11I NORMAN G. TORCHIN, Primary Examiner R. E. FICHTER, Assistant Examiner US. Cl. X.R. 96-107 

